Since the late 1980s, restrictive policies and measures on immigration (e.g. limiting the number of visas available) and the tightening and militarization of the U.S. southern border have kept potentially undocumented Mexican migrants in the country. With higher costs and risks at the border for undocumented migrants, research suggests that the choice to stay in the United States, rather than moving back and forth over the border, is more of a necessity today than ever before.

On the other hand, as undocumented Mexican migration to the United States wanes — driven also by demographic changes in Mexico — undocumented migration from Central America is increasing. This shift is largely caused by civil wars in the region that sent refugees north, subsequent U.S. immigration policies of the 1990s that expelled many of these refugees that had criminal records, and the social instability in Central America that continues to drive migration back to the United States.

And these policies not only drive the movement of peoples, but also the transfer of their monies. Recent research shows that legal status in the United States (or lack thereof) affects decisions to send money and travel to home countries. For example, Salvadorans — many of whom arrived in the United States undocumented — sent remittances at high rates than other national groups, though traveled back home less than half the rate of the typical Latino migrant. This same research finds that Mexican migrants were more likely to travel back to their home country than Cubans (as travel home was tightly restricted), though both sent remittances at similar frequencies.